Sheet-rock cutter



March 30 1926.

N. SMITH ET AL SHEET ROCK CUTTER Filed July 11, 1925 2 Sheets-Sheet 1 INVENTOR "n. 5111 March 30 1926. 1,578,477

v N. SMITH ET AL SHEET ROCK CUTTER Filed July 11, 19 25 2 Sheets-Sheet 2 Patented Mar. 30, 1926.

UNITED J STATES;

NORMAN SMITH AND FRED W. GALLAGHER, on Lmoomt PARK, NEW JEnsEY; V

; Application filed my 11, 1925. Serial in. 43,054..

ToaZZ whom it may 00720017 21 v Be it known that we, NORMAN 'SMITIrand FRED 3V. GALL GHER, subjects of King George V, residing at Lincoln Park, in the county of Morris and State of NeWJersey,

have invented certain new and useful Improvements in Sheet-Rock Cutters, of which the following is a specification.

This invention relatestoiniplelnents for use in'marking lines on and forming incisions in sheet material-and it has for its principal object to provide an implement of this class which may be used with great ad;- vantage in cutting material like that known as sheet-rock, which is a sheet of layers of plaster and paper or other fibrous material with the paper layers the exposed ones and. which on account. of the usual considerable size of the sheet and the brittle nature of the plaster it is difiicultto cut with accuracy by any method involving first markingofi the' line of the cut with a pencil andthen cutting the sheet-along such linewith a saw, using a mere rule or straight edge as a guide in the marking and cutting. w a

In the drawings,

7 Fig. lis aplan ofthe implement, showing it in operat ve position one sheet of the ma f terlal to be operated upon;

I Fig. 2 is an elevation, viewing'the implejforms whatmay be taken as its base. In the present case this base is formed by a straight bar a which has secured theretocentrally thereof a'triangular plate. 6 with one apex thereof projecting laterally of the bar. The remainder of the frame is formed by another straight bar 0 arranged perpendieularly to bar a and having one end removably secured on" the top of the plate by screws (Z. The bar 0 is removable so that when not an use the frame may be knocked down for packing in smaller compass. The frame has a handle formed by two posts 6 rigidly upstanding from the barc and a handle porper "f bridging them. I

On vertical pivotsformed by screws 5/ tapped into the under side of the bar a at regular intervals lengthwise thereof and in alinementwitheach other are j'o-urnaled a plurality of per pherally grooved Wheels 72.;

there are preferably two at leastof these" wheels at EZtCllSKlO ofthe center of the bar (1 The barrels h of these wheels aresinall n diameter relatively to their flangeshfi, so

that the grooves of the wheels are quite deep.

On the bar arranged the tool-heath which inthe present example compriseslthe agonal block z'having ascrew j tapped-into conical head .j; and a metal strap labent ATENTa F I E.

following par-ts and which with the fra'nie; forms anad ust-abIe support ng structure- 7 for the wheels and the tool-holder: A hex- 70 it centrallythereof and fOrmedWith around three sides of the block and having itsends projecting upwardly fand forming,

with thehandleprop'er Z; a .handle forithe head is "and 2' 138111 secured to ether b", 7 t? b y screws -70. Fig. 4.; The tool-.headhas a hole on extending therethrough axially 'of; screw j, and this hole, which is of the same polygonal cross-section as bar 'e, receives the lat; ter w1th asnuglfitgitis ad ustable toward and from the mentionedbase portion of the frame and may' be secured where adjusted by an upstanding thunib-screw n .tapped into the head in a position convenient tofthe hand of the operator, towit, within the arch formed by the handle le l. It =will be understoodthat the screw is in effect but a threaded stem projecting from the block 2',

itsj threaded connection therewith having. nothing to do with the normal use ofthe" implement. L r I The tool-holder is formed in the present case by a bushing 0 having a conical orifice 0. to receive and fit the conical head 7"--of the screw or stem y'fwhich itreceives. :At

three equidistant, points thereon it carries the tools as a rota'r cutter whose axis 1 7 T Y p parallel with the bar a. a bevel cutter blade 'p set at an angle to said bar 0, and a pencil or other marker 79 held in radial position in the bushing. Suit-able screws Q and 9 maybe used to secure the tools removably i in place. 'lhe bushing is rotatably adjust able on the bearingffornied the stem or screw to brin ian one of the tools into o'perativeposition (projecting downwz rrdly, i

as pQ Fig. 5) and is held when'adjusted by a'nut 7 screwed on steni yand adapted'to "L j i H t 1, 1am the bushing against the abutment formed by head 7" ofsaid stem; a key or feather s on the head j" may at this time enter any one'o t three grooves t in the bushing (Fig. 7) jto"insure the latter against turning.

In use the sheet A to be cutie-laid upon a'table B so that one edge projects some-i What; Then the operator places the imple' jment' on the sheet in the manner shown in, J Figs. '1 and 2, i. e., so -that the appropriatev one or the tools rests on the sheet and all the wheels receive in their grooves the pro jecting edge of thesheet and their barrels all bear against-the same. The head having been first adjusted the desired distance from the base ot the implement the operatornow grasps thelatter by its two, handles and shifts it across the sheet; in doing so. he maintains the Wheels inoontact'with the 'projecting-edge of the sheet and in this 'way'obtains a mark on or cut in the sheet Wl'iich "truly parallel uwitli said edge. 1 In cut ting the mentioned sheet rock the "cutter-(72" tor 19 will incise the outer paper layer, so

that the sheet may thenbe broken on line of cut, which-Will be sharply defined as Well as truly-paralleltotheprojecting or guiding edgeo'i: the sheet. 7 The considerable sizeot he sheet, the briti tlenature of the plaster thereof, the fact that the edge of the sheetfivhich serves" as the gu d ng edge is not always withoutlrregur larlties and other considerations make it dosirable to provide Wheels or rollers, as h,

i having grooved peripheries to receive the edge of thesheet and to provide a plurality of these oneach side of the center of the base portion ofthe' frameso-as to guide the implement true when the bar a (which repres sents its longitudinal or Working. axis) is bebars a and a secured together-in the form of the letter T, with the top of the T (bar i A) a yond a corner of the sheet.

Ace'nte'r-point u may be adapted to be set in a hole 1) arranged centrally of bar a so as toproject"downwardly. When this is rested on some point of the sheet the implement anay be employed to" form an'arcuate mark on or out in the'sheetof any radius'acoording to the adjustment of the tool-head alongbar c, V .7 i 1 It is an important feature ofthe invention that the frame is made desirably light by forming it principally of two slender forming the base of the frame and the upright ot the? (bar: forming a sup- Iport for and along Whichfthe tool is adjust able, and sa d base havingfguidlng means.

(as h) to bearonfan edge otthe sheet.

Having thus tully describ-edg ourinven- I tion, What We cla1n1. and des1re to obtaln by Letters Patent is 5 1, In an mplementof the class described,

" the'coinbination of a framehaving a basalportion, 'aset of peripherally grooved freely revoluble guiding Wheels arranged in alinement with each otheron said portion, the

frame'including also anotherportion pr0-w H jecting rigidly from the basal portion in angular relation to the set of Wheels, and a tool-head adjustable on the latter portion to-.'

Ward and fromthe basal portion.

2. In an .implementof the class described,

the combination oat frame having a basal portion, a set of peripherally grooved freely rcvoluble guiding Wheels arranged in alineinent Witl'r each other on said portion, the

3. In animplementof the class described,

the combination, with a supporting structure the sheet to be operated upon, said snaicture also including a' bearing- Whose axis projects laterally away, from the basal port on, and

frame including also; another portion proccting rigidly iii-om the basal portionin including a basalipc'rtion having rine ans to J confine said structure in a definitepath over a tool-head supported by said bearing and adjustable aro'undsaid axis;

4.. In an implement of the class described, 7'

the combination, with supporting structure including a basal portion having means to confine said structurefin. a definite pathover the sheet to] be "operated upon, sail structure a'l'so including *a bearing'fforined with an abutment and iavin its'aX-is pro-t j'ecting laterally from the basal po1= tron, a tool-head supported by sa d bearing and revoluble' around said "a aisfand a nut screwed on the bearing and adapted to j'am i the tool-head againstthe abutment.

" '5, In an implement ofthe class described,

the combination, With a frame including a basal portion having means to'confine the frame in a definite path over the sheet to beoperated upon, sardftrame also including an elongated portion extending laterally away from the basal portion, atool-head shifta-ble on tliesecond-named' portion toward and from the basal portion, said basal portion and tool-head having upstanding handles and the latter handlebeing arched, and a screw tapped Into the head-Withinthe arch olf sa'id latter handle and ,ada-ptedto bear against said second-named portion of the frame. V v I 1 testimony whereof We EllfiX our signatures. I

NQRMAN SMITH, FRED W. GALLAGHER, 

